It is now expected that newly commissioned wind power plants and other forms of renewable energy are able to regulate the power that they provide to a grid. A wind power plant comprises a plurality of wind turbine generators and is also known as a wind park or a wind farm. The regulation and general operation of the power plant is controlled by a power plant control system or controller (PPC), which implements operational limits and requirements as set out by a Transmission System Operator (TSO) or in country-specific grid interconnection requirements or ‘grid codes’. The TSO also communicates power delivery demands to the PPC.
Grid codes commonly include specific restrictions on reactive power exchange at a Point of Interconnection (PoI) between the grid and the power plant. These restrictions are governed by so-called P-Q charts, which outline the grid code requirements for reactive power exchange limits based on real power output. The PPC implements power delivery demands received from the TSO, whilst ensuring that the limits and requirements set out in the P-Q charts are upheld.
However, limiting reactive power exchange based only upon active power measurements can result in disconnection of individual generators within the power plant, disconnection of the power plant as a whole, or even grid instability.
It is an aim of the present invention to address disadvantages associated with the prior art.